Portable power managers for mobile off-grid applications are known. Examples include man-wearable and man-packable power managers e.g. the SPM 611/612, manufactured by Protonex Technology Corp of Southborough, Mass. and the SFC Power Manager 3G by SFC of Brunnthal-Nord, Germany. One example of a conventional power manager is disclosed in U.S. Patent Application Publication No. 2007/0257654. Conventional portable power managers connect with one or more rechargeable batteries or other portably power sources and with one or more power loads. The power manager receives input power from the connected power sources and delivers output power to the connected power loads. If needed, input and/or output power may be converted to another form, such and a different voltage, before being delivered to a power load.
Power distribution networks usable to deliver power from a single power source to multiple electronic devices such as for passenger use in vehicles or other areas where grid power is not readily available are known. An example of a conventional power supply connection system is disclosed in U.S. Pat. No. 5,570,002 by Castleman, entitled “Universal Power-Supply Connection System For Multiple Electronic Devices.” As disclosed in Castleman, a single power supply is connected to one or more power loads over a power distribution system. The power distribution system includes an input port for connecting the power supply to the power distribution system and a plurality of output ports for connecting the one or more power loads to the power distribution system. The power distribution system includes a digital electronic microprocessor and a reprogrammable system memory. Each power load includes a load memory disposed in the power load itself or in a cable connecting the power load to the power distribution system. The load memory stores information specific to a corresponding power load such as a category of the device or the power specifications of the power load.
The power distribution system includes one or more voltage regulators and/or controllable regulators disposed between the power source and each of the output ports. Additionally, each port includes a data channel connectable between the microprocessor and the load memory for reading and perhaps reformatting the information stored thereon. In operation, the power distribution system obtains information from the load memory, determines if the power load can or should be connected to the power distribution system and if yes, configures the one or more voltage regulators and/or controllable regulators disposed between the power source and the connected power load to deliver power to the power load with appropriate power characteristics. In addition, Castleman teaches that a controllable regulator can be deactivated to disconnect a power load from an output port. One problem with Castleman is that only one power supply is available for use. Accordingly, a failure of the single power supply necessarily results in a loss of power in all of the connected power loads. Another problem with Castleman is that each output port requires a dedicated controllable power regulator increasing the weight and the cost of the power distribution system. Accordingly, there is a need in the art for a power distribution system than can readily connect with a plurality of power supplies and especially a plurality of portable power supplies. Moreover, there is a need in the art for a power distribution system that can readily connect with a plurality of power supplies while drawing power from one power supply at a time. Additionally, there is a need in the art for a power distribution system that will not experience a power interruption to connected power loads when a connected power supply is suddenly disconnected from the power bus, becomes discharged, or otherwise becomes unexpectedly unable to deliver power.
Conventional portable power managers are known that are capable of connecting to two or more external power sources simultaneously. In addition, conventional power managers connect to, read and possibly reformat information or data stored on connected power devices including reading information from power sources such as external batteries or power generators and from external power loads. Typically, the conventional power manager includes a power bus connected to each device port. The power bus operates at a substantially constant bus voltage such that external power devices that can operate at the bus voltage are directly connected to the power bus to exchange energy. In addition, some ports may include a power converter connected between the power bus and the device port to convert input power signals received from a connected external power source to the bus voltage and to convert output power signals delivered from the power bus to a voltage suitable for operating a connected external power load.
While U.S. Patent Application Publication No. 2007/0257654 by Krajcovic et al. entitled “Power Manager Apparatus,” describes the need to disconnect and/or current limit connected power loads to conserve power for higher priority power loads they only provide two output ports that are coupled to the power bus over a buck converter. Accordingly, only two power loads can be disconnected or current limited by the buck converters and all other power loads remain connected to the power bus without possibility for disconnect. Moreover any power loads connected to device ports that do not include buck converters have to match the power value at the power bus in order to be powered by the power manager.
Generally, there is a need in the art for an improved power manager port connection and especially one that allows every port to dynamically connect or disconnect a power device to or from the power bus. Additionally there is a need in the art for an improved power manager port connection that allows every port to be selectively connected directly to the power bus or connected to the power bus over a controllable power converter based on information read from the power device. In another instance, there is a need to continue to power essential devices even when changing from one power source to another or when a power source becomes suddenly and unexpectedly unable to meet the power demands of connected power loads. Accordingly, there is a need to rapidly connect a backup power supply to the power bus in response to unmet power demands.
Conventional man-portable power managers are portable and carried by infantry soldiers; any reduction in size and weight is favorably viewed. As shown by Krajcivic et al. in FIGS. 2 and 3 of U.S. Patent Application Publication No. 2007/0257654, port connectors are disposed on opposing longitudinal sides of the power manager such that a transverse width of the disclosed power manager is more than two times a longitudinal length of a port connector. Moreover, the ports are crowded together and may be difficult to connect to due to the crowding. There is a need in the art to reduce port crowding without increasing the size or weight of the device.
In man-portable, off grid applications, such as battlefields, non-rechargeable batteries such as the BA-5590 are used as a power source connected to conventional power managers. To avoid discarding BA-5590 with 30% to 50% of the rated charge still remaining on the batteries, some non-rechargeable batteries provide indicators that indicate the amount of charge remaining in the battery. These indicators are often physical, such as a strip on the side of a battery or an LED charge level indicator built into the battery to show how much energy is in reserve. One problem with the BA-5590-style charge level indicators is that they have low resolution. In particular, on a BA-5590, there are 5 LED lights showing 100% capacity when all 5 lights are on, 80% capacity when 4 lights are on, 60% capacity when 3 lights are on, 40% capacity when two lights are on, 20% capacity when one light is on and empty or no charge remaining when no lights are on. In most situations, a user will discard the battery when one or two lights are on in order to avoid a loss of power when the battery becomes completely discharged. As a result, many batteries are discarded with between 20 and 40% of the charge capacity unused. Accordingly, there is a need in the art to more fully utilize the charge remaining on non-rechargeable batteries connected to a power manager.
The charge remaining on many rechargeable batteries, e.g. lithium sulfur dioxide (LiSO2) and lithium magnesium dioxide (LiMnO2) is not easily detected using conventional terminal voltage measurements, so more sophisticated and more expensive coulomb counting devices are integrated into these rechargeable batteries and are used to predict the charge level remaining on the rechargeable battery. One advantage of coulomb counters is that they have a higher resolution than LED charge level indicators. For example, a coulomb counter may be able to discern 20 levels of charge capacity with only the last 5% remaining uncertain. However, a coulomb counter does not provide a visible indicator of remaining charge level and a user cannot check the charge level of a rechargeable battery that uses a coulomb counter without connecting the battery to a device capable of reading data from the battery. As a result, these batteries are often discarded after one use simply because the user is uncertain about how much charge is remaining on the battery. Accordingly, there is a need in the art to more fully utilize the charge remaining on rechargeable batteries connected to a power manager without an unexpected power interruption even when the charge level on the rechargeable batteries is uncertain. In addition, it is desirable to eliminate a coulomb counter from rechargeable batteries used with portable power manager to reduce the cost and complexity of the batteries.